US4009299A - Tin strip formulation for metal to glass seal diodes - Google Patents
Tin strip formulation for metal to glass seal diodes Download PDFInfo
- Publication number
- US4009299A US4009299A US05/624,681 US62468175A US4009299A US 4009299 A US4009299 A US 4009299A US 62468175 A US62468175 A US 62468175A US 4009299 A US4009299 A US 4009299A
- Authority
- US
- United States
- Prior art keywords
- tin
- diodes
- percent
- metal
- devices
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02041—Cleaning
- H01L21/02043—Cleaning before device manufacture, i.e. Begin-Of-Line process
- H01L21/02052—Wet cleaning only
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/10—Etching compositions
- C23F1/14—Aqueous compositions
- C23F1/16—Acidic compositions
- C23F1/30—Acidic compositions for etching other metallic material
Definitions
- This invention relates to the manufacture of semiconductor devices and more particularly to the manufacture of semi-conductor diodes having tin plated leads.
- a semiconductor device is manufactured by assembling a semi-conductor chip with metal slugs within a glass tube and then sealing the members together. Leads extending therefrom are plated with tin to permit ready connection of the devices into circuits. The tin plating may result in rejection of otherwise electrically satisfactory devices.
- a further object of the invention is to provide a reclamation process for semiconductor devices having glass-to-metal seals.
- a semiconductor die or chip has a pair of metal slugs bonded to respective surfaces of the die. Terminal conductors are attached to and extend axially from the slugs and a glass sleeve is bonded around the slugs.
- the semiconductor device leads are plated, as in a sulfuric acid-stannous sulfate bath with tin. In some cases, because of surface conditions of the bath or conditions of the leads, the plating is non-adherent or less than sufficient thickness to satisfy quality inspection. Since the device is electrically satisfactory except for the plating, the plating should be removed prior to again replating the conductors.
- a stripping solution consisting of 5 - 20 percent trichloroacetic acid, 0.1 to 5 percent of a compound selected from the group consisting of cationic, anionic, and nonionic surfactants and the balance water.
- the defective diodes are immersed therein for approximately 5 - 10 minutes while the solution has preferably maintained at a temperature of approximately 100° C. Treatment in accordance with the above, effectively removes the defective tin plating from the devices and the devices may then be replated.
- Cationic surfactants may be a di- or tri-alkyl amine hydrochloride such as a trialkanol amine hydrochloride where alkanol is 2 - hydroxy ethyl and 2 - alkyd amine.
- Anionic surfactants may be a sodium slat of a dialkyl sulfosuccinic acid where alkyl is octyl or dodecyl benzene sulfonate.
- a nonionic may be one of a homologous series of nonyl phenoxy polyethanols.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Chemically Coating (AREA)
Abstract
Immersion of semiconductor devices, particularly diodes, having a defective tin plating thereon in a solution of 5 - 20 percent by weight trichloroacetic acid, 0.1 to 5 percent by weight of a compound selected from the group consisting of cationic, anionic, and nonionic surfactants and the balance water effectively removes the tin therefrom. The process is effective at room temperature but preferably is performed at approximately 100° C.
Description
A related application, Ser. No. 430,431, filed Jan. 3, 1974 by Richard L. Greeson and Elliott M. Philofsky, and assigned to the same assignee as herein is copending.
This invention relates to the manufacture of semiconductor devices and more particularly to the manufacture of semi-conductor diodes having tin plated leads.
As disclosed in the above mentioned related application, a semiconductor device is manufactured by assembling a semi-conductor chip with metal slugs within a glass tube and then sealing the members together. Leads extending therefrom are plated with tin to permit ready connection of the devices into circuits. The tin plating may result in rejection of otherwise electrically satisfactory devices.
Previous attempts to remove the defective plating, as by a dilute hydrochloric acid solution, has not been satisfactory because such stripping solutions also attack the borate glass-to-metal seal.
It is an object of the invention to provide an improved process for the stripping of tin plating, particularly from semiconductor diodes.
A further object of the invention is to provide a reclamation process for semiconductor devices having glass-to-metal seals.
In accordance with these objects, there is provided a process for reclaiming semiconductor devices comprising the steps of:
PROVIDING A SEMICONDUCTOR DEVICE HAVING A DEFECTIVE TIN PLATING ON THE LEADS THEREOF; AND
Immersing said devices in a solution of 5 - 20 percent by weight trichloroacetic acid, 0.1 to 5 percent by weight of a compound selected from the group consisting of cationic, anionic, and nonionic surfactants, and the balance water for a period of time sufficient to strip the tin therefrom.
In the manufacture of a semiconductor device which may be, for example, a zener diode, a semiconductor die or chip has a pair of metal slugs bonded to respective surfaces of the die. Terminal conductors are attached to and extend axially from the slugs and a glass sleeve is bonded around the slugs. To prepare the completed device for attachment as to a circuit board, the semiconductor device leads are plated, as in a sulfuric acid-stannous sulfate bath with tin. In some cases, because of surface conditions of the bath or conditions of the leads, the plating is non-adherent or less than sufficient thickness to satisfy quality inspection. Since the device is electrically satisfactory except for the plating, the plating should be removed prior to again replating the conductors.
In accordance with this invention, there is provided a stripping solution consisting of 5 - 20 percent trichloroacetic acid, 0.1 to 5 percent of a compound selected from the group consisting of cationic, anionic, and nonionic surfactants and the balance water. The defective diodes are immersed therein for approximately 5 - 10 minutes while the solution has preferably maintained at a temperature of approximately 100° C. Treatment in accordance with the above, effectively removes the defective tin plating from the devices and the devices may then be replated.
Cationic surfactants may be a di- or tri-alkyl amine hydrochloride such as a trialkanol amine hydrochloride where alkanol is 2 - hydroxy ethyl and 2 - alkyd amine. Anionic surfactants may be a sodium slat of a dialkyl sulfosuccinic acid where alkyl is octyl or dodecyl benzene sulfonate. A nonionic may be one of a homologous series of nonyl phenoxy polyethanols.
Particular examples of the effectiveness of the process is given in the following examples:
__________________________________________________________________________ TCA Surfactant Solution Time to Example (%W) (%W) Temp (° C) Clear (min) Comments __________________________________________________________________________ 1 5 0 25 195 Small spots on tin left, dull finish 2 5 0.5 AOT 25 170 No tin left, no spots, matte finish 3 10 0 25 90 Like No. 1, smaller spots of tin left 4 10 .5 AOT 25 75 Like No. 2, shinier finish 5 15 0 25 65 A few tiny tin spots, satin finish 6 15 .5 AOT 25 55 Free of all tin, specular finish 7 5 .1 CO 880 100 7.5 No tin seen, matte finish 8 10 0 100 5 A few islands of slower reacting tin (2-4 mils), dull 9 10 .1 CO 880 100 3.5 Very clean, shiney 10 15 .1 CO 880 100 2.2 Very clean, specular basis metal 11 10 .5 DBS 100 4.0 Clean satin finish 12 10 0.1 DDPA 100 3.5 Very clean, shiney 13 10 .5 DDPA 100 2.5 Very clean, specular 14 10 .1 BDEA 80 4.5 Very clean, shiney 15 10 .5 BDEA 80 6.0 Very clean, specular Surfactants given in the above are: (1) AOT is Aerosol AOT by American Cyanimid which is a sodium salt of a dialkyl sulfosuccinic acid where alkyl is octyl. (2) DBS is dodecyl benzene sulfonate. (3) CO 880 is Igepal CO 880 by GAF which is a nonionic surfactant (4) DDPA is didodcyl phenylamine hydrochloride. (5) BDEA is benzl dodecyl ethanol amine hydrochloride. __________________________________________________________________________
Thus, it will be seen that there is provided an effective treatment for the stripping of the tin from tin plated semiconductor devices particularly diodes which is effective and economic.
Claims (3)
1. A process for the reclamation of semiconductor devices comprising:
providing semiconductor devices having a defective tin plating thereon; and
immersing said devices, for about 5-10 minutes, in a solution of 5-20 percent by weight trichloroacetic acid, 0.1 to 5 percent by weight of a compound selected from the group consisting of cationic, anionic, nonionic surfactants, and the balance water.
2. A process as recited in claim 1 wherein said solution is maintained at a temperature of approximately 100° C.
3. A process as recited in claim 2 and further including the step of replating said devices in a sulfuric acid (stannous sulfate solution).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US05/624,681 US4009299A (en) | 1975-10-22 | 1975-10-22 | Tin strip formulation for metal to glass seal diodes |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US05/624,681 US4009299A (en) | 1975-10-22 | 1975-10-22 | Tin strip formulation for metal to glass seal diodes |
Publications (1)
Publication Number | Publication Date |
---|---|
US4009299A true US4009299A (en) | 1977-02-22 |
Family
ID=24502908
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US05/624,681 Expired - Lifetime US4009299A (en) | 1975-10-22 | 1975-10-22 | Tin strip formulation for metal to glass seal diodes |
Country Status (1)
Country | Link |
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US (1) | US4009299A (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2480793A1 (en) * | 1980-04-17 | 1981-10-23 | Dart Ind Inc | COMPOSITION BASED ON PEROXIDE AND ADDITIONAL FLUORIDE OF POLYACRYLAMIDE FOR DECAPPING METALS AND APPLICATIONS THEREOF |
US4439338A (en) * | 1981-10-14 | 1984-03-27 | Alfachimici S.P.A. | Solution for stripping a layer of tin or tin-lead alloy from a substrate by means of a spraying operation |
EP0698917A1 (en) * | 1994-08-25 | 1996-02-28 | Wacker-Siltronic Gesellschaft für Halbleitermaterialien mbH | Cleaning agent and process for cleaning semiconductor wafers |
US5923946A (en) * | 1997-04-17 | 1999-07-13 | Cree Research, Inc. | Recovery of surface-ready silicon carbide substrates |
US6037271A (en) * | 1998-10-21 | 2000-03-14 | Fsi International, Inc. | Low haze wafer treatment process |
CN105723005A (en) * | 2013-07-08 | 2016-06-29 | 阿尔法金属公司 | Metal recovery |
WO2019057278A1 (en) * | 2017-09-20 | 2019-03-28 | Hp Indigo B.V. | Pre-treatment composition |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2721119A (en) * | 1953-05-14 | 1955-10-18 | Gen Motors Corp | Stripping tin from copper |
US3072579A (en) * | 1959-10-28 | 1963-01-08 | Kenneth W Newman | Method of removing epoxy, silicone and melamine coatings |
-
1975
- 1975-10-22 US US05/624,681 patent/US4009299A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2721119A (en) * | 1953-05-14 | 1955-10-18 | Gen Motors Corp | Stripping tin from copper |
US3072579A (en) * | 1959-10-28 | 1963-01-08 | Kenneth W Newman | Method of removing epoxy, silicone and melamine coatings |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2480793A1 (en) * | 1980-04-17 | 1981-10-23 | Dart Ind Inc | COMPOSITION BASED ON PEROXIDE AND ADDITIONAL FLUORIDE OF POLYACRYLAMIDE FOR DECAPPING METALS AND APPLICATIONS THEREOF |
US4439338A (en) * | 1981-10-14 | 1984-03-27 | Alfachimici S.P.A. | Solution for stripping a layer of tin or tin-lead alloy from a substrate by means of a spraying operation |
EP0698917A1 (en) * | 1994-08-25 | 1996-02-28 | Wacker-Siltronic Gesellschaft für Halbleitermaterialien mbH | Cleaning agent and process for cleaning semiconductor wafers |
US5695572A (en) * | 1994-08-25 | 1997-12-09 | Wacker Siltronic Gesellschaft Fur Halbleitermaterialien Aktiengesellschaft | Cleaning agent and method for cleaning semiconductor wafers |
CN1057330C (en) * | 1994-08-25 | 2000-10-11 | 瓦克硅电子半导体材料有限公司 | Cleaning agent and method for cleaning semiconductor wafers |
US5923946A (en) * | 1997-04-17 | 1999-07-13 | Cree Research, Inc. | Recovery of surface-ready silicon carbide substrates |
US6037271A (en) * | 1998-10-21 | 2000-03-14 | Fsi International, Inc. | Low haze wafer treatment process |
CN105723005A (en) * | 2013-07-08 | 2016-06-29 | 阿尔法金属公司 | Metal recovery |
WO2019057278A1 (en) * | 2017-09-20 | 2019-03-28 | Hp Indigo B.V. | Pre-treatment composition |
CN110741056A (en) * | 2017-09-20 | 2020-01-31 | 惠普印迪戈股份公司 | Pretreatment composition |
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